The Château d'Eu is a former royal residence built in the 16th century to replace an earlier one purposely demolished in 1475 to prevent its capture by the English. The chapel contains the tombs of Henry I, Duke of Guise, and his wife, Catherine de Clèves, who embarked on the construction of the château in 1578. The building was completed almost a century later by the Anne Marie Louise d'Orléans, Duchess of Montpensier.
Between 1830 and 1848, the château, which had been the property of the Orléans family since its acquisition by La Grande Mademoiselle in October 1657, served as King Louis-Philippe's summer residence. Her Imperial Highness Isabel, Princess Imperial of Brazil, who brought slavery to an end in Brazil in 1888, died at the Château in 1921. Her husband was Prince Gaston, Count of Eu, a grandson of King Louis Philippe I, friend of Queen Victoria.
In 1964, the city of Eu acquired the château, in which, in 1973, it installed its City Hall and created the Musée Louis-Philippe.References:
First record of Kastelholma (or Kastelholm) castle is from the year 1388 in the contract of Queen Margaret I of Denmark, where a large portion of the inheritance of Bo Jonsson Grip was given to the queen. The heyday of the castle was in the 15th and 16th centuries when it was administrated by Danish and Swedish kings and stewards of the realms. Kastelhoma was expanded and enhanced several times.
In the end of 16th century castle was owned by the previous queen Catherine Jagellon (Stenbock), an enemy of the King of Sweden Eric XIV. King Eric conquered Kastelholma in 1599 and all defending officers were taken to Turku and executed. The castle was damaged under the siege and it took 30 years to renovate it.
In 1634 Åland was joined with the County of Åbo and Björneborg and Kastelholma lost its administrative status.